Piston actuated pressure responsive switch with recenter contact adjustment means

ABSTRACT

A pressure responsive switch for indicating the loss of pressure in a vehicle brake line with the switch being actuated by piston movement through a swivel or toggle arrangement including a contact ring which is engaged by a contact to complete a circuit when hydraulic pressure occurs. The contact remains in electrical engagement after the toggle returns to its center position. The switch has a stem which is pressed inwardly to recenter the contact after the brake system has been repaired.

ilnited States Patent 1 Rake [ June 12, 1973 PISTON ACTUATED PRESSURERESPONSIVE SWITCH WITH RECENTER CONTACT ADJUSTMENT MEANS 75 Inventor:Richard c. Rike, Dayton, Ohio [73] Assignee: General ElectricCorporation,

Detroit, Mich.

[22] Filed: Sept. 1, 1971 [21] Appl. No.: 176,972

[52] U.S. Cl. 200/82 D, 200/81.9 R, 200/82 R [51] Int. Cl. H0lh 35/38[58] Field of Search 200/8l.9 R, 82, 16 C,

200/82 R, 82 D, 83 R [56] References Cited UNITED STATES PATENTS3,662,370 5/1972 Barnes et a1. 200/82 D X 3,610,853 10/1971 Reznicek200/82 D 1,806,777 5/1931 Wiley 200/16 C 941,053 11/1909 Young ZOO/81.9R

1,812,410 6/1931 Mever 200/16 C 2,121,433 6/1938 Kettunen 200/82 R X2,244,373 6/1941 Powers ZOO/81.9 R X 2,583,814 1/1952 Burklin ZOO/81.9 RX 3,336,451 8/1967 Burton 200/82 D Primary Examiner-1 R. Scott AttorneyF. J. Soucek and C. R. Engle [57] ABSTRACT A pressure responsive switchfor indicating the loss of pressure in a vehicle brake line with theswitch being actuated by piston movement through a swivel or togglearrangement including a contact ring which is engaged by a contact tocomplete a circuit when hydraulic pressure occurs. The contact remainsin electrical engagement after the toggle returns to its centerposition. The switch has a stem which is pressed inwardly to recenterthe contact after the brake system has been repaired.

1 Claim, 2 Drawing Figures PISTON ACTUATED PRESSURE RESPONSIVE SWITCHWITH RECENTER CONTACT ADJUSTMENT MEANS This invention relates generallyto a pressure responsive switch and more particularly to a switch forsignaling the loss of pressure within the braking system of a motorvehicle.

Conventional braking systems employ a dual master cylinder which has twohydraulic or pneumatic working chambers to supply fluid independently tothe front wheel brakes and the rear wheel brakes. If a leak occurs inone line there will be no loss of pressure in the other line and thevehicle will be capable of stopping.

In systems utilizing a dual master cylinder it is desirable to providemeans for warning the operator of the vehicle if there is leakage ineither the front or rear lines of the braking system.

It is, therefore, a principal object of the present invention to providea means for sensing the loss of pressure in either the front or rearlines of a braking system employing a dual master cylinder.

It is a further object to provide switch means in a braking system whichmeans is responsive to aloss in pressure in one of the lines and whichmeans may be manually reset after the braking system has been repaired.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon reading the followingdescription when taken in conjunction with the drawing wherein likereference numerals refer to like parts and wherein:

FIG. 1 is. an elevational view in section of the pressure responsiveswitch of the present invention, and

FIG. 2 is a sectional view ofa portion of FIG. 1 showing the switch ofthe present invention in an actuated position.

Referring to FIG. 1, the switch includes a housing having a top portion2 of plastic or other nonconducting material and a steel base portion 4.Positioned within the housing are a pair of contact rings 5 and 6separated from each other by an insulator ring 7. A rod-like terminal 8having a pointed end 8' is vertically movable within the housing and iselectrically connected to the contact ring 5 by means of a spring 9. Acontact plate 11 having an aperture 11' therein is slidably movablewithin the housing and is adapted to bridge the contact rings 5 and 6 tocomplete a circuit therethrough. The contact plate 11 is coupled to aplastic toggle member 12 by means of a centering spring 13. The togglemember 12 has a cylindrical aperture 12' at its upper end and has alower end 14 connected to a piston assembly 15 positioned in a conduit16 of a brake system. An electric alarm circuit including a battery 17and an alarm or indicator 18 is connected between the base 4 of thehousing and the terminal 8.

As shown in FIG. 2, as pressure in one side of conduit 16 decreases, thepiston assembly moves toward the left, for example, and tilts the top oftoggle member 12 to the right. Acting through the spring 13, the togglemember causes contact plate 11 to shift to the right and complete acircuit through contact rings 5 and 6. A circuit is thus completedthrough the battery 17 and indicator 18 by means of the terminal 8,spring 9, ring 5, contact plate 11, ring 6 and base 4.

To reset the switch after it has been actuated, the rod-like terminal 8is pushed down until the end 8 enters the apertures 11 and 12' to centerthe contact plate 11 and the toggle member 12. I

Contact plate 11 then no longer bridges the contact rings 5 and 6 andthe circuit for battery 17 and indicator 18 is broken.

It is obvious that different modifications and embodiments may be madewithout departing from the scope of the invention as defined in thefollowing claims.

What is claimed is:

' 1. A pressure responsive switch assembly for indicating a loss ofpressure in a pressurized system comprising a switch housing having atop portion of nonconductive material and a base portion of conductivematerial, a pair of contact rings positioned in said base portion withone of said rings contacting said base portion, an insulating memberpositioned between said rings to separate said rings and to insulate theother of said rings from said base portion, a contact plate having anaperture therethrough and being in contact with said other of saidrings, said contact member being slidable in said housing to bridge saidrings and provide electrical contact therebetween, a toggle member ofinsulating material tiltably mounted in said base portion and having anaperture in the top end thereof, first spring means positioned betweensaid toggle member and said contact member and biasing said contactmember against said other of said rings, said toggle member having alower end adapted to engage a piston assembly in said pressurizedsystem, a rod-like terminal positioned in the top portion of said switchhousing and being vertically slidable in said housing, said terminalhaving a pointed lower end adapted to pass through the aperture in saidcontact plate and enter the aperture in said toggle member, and secondspring means between said terminal and said other of said contact ringsto provide an electrical connection therebetween, said second springmeans normally biasing said terminal outwardly with respect to saidhousing.

a: k s:

1. A pressure responsive switch assembly for indicating a loss ofpressure in a pressurized system comprising a switch housing having atop portion of nonconductive material and a base portion of conductivematerial, a pair of contact rings positioned in said base portion withone of said rings contacting said base portion, an insulating memberpositioned between said rings to separate said rings and to insulate theother of said rings from said base portion, a contact plate having anaperture therethrough and being in contact with said other of saidrings, said contact member being slidable in said housing to bridge saidrings and provide electrical contact therebetween, a toggle member ofinsulating material tiltably mounted in said base portion and having anaperture in the top end thereof, first spring means positioned betweensaid toggle member and said contact member and biasing said contactmember against said other of said rings, said toggle member having alower end adapted to engage a piston assembly in said pressurizedsystem, a rod-like terminal positioned in the top portion of said switchhousing and being vertically slidable in said housing, said terminalhaving a pointed lower end adapted to pass through the aperture in saidcontact plate and enter the aperture in said toggle member, and secondspring means between said terminal and said other of said contact ringsto provide an electrical connection therebetween, said second springmeans normally biasing said terminal outwardly with respect to saidhousing.